Chaser, a 9-year-old border collie that gained fame for understanding more than 1,000 English words, now has shown that she can understand sentences. And not just two-word sentences, such as "fetch stick" or "paw ball" -- but sentences containing a prepositional object, verb, and direct object.

You go, girl.

"Chaser intuitively discovered how to comprehend sentences based on lots of background learning about different types of words," Dr. John Pilley, Chaser's owner and a retired psychology professor at Wofford College in South Carolina, told ScienceNews.

Dr. Pilley, the author of a new study about Chaser's abilities, previously taught her how to recognize objects by name, as well as verbs and prepositions in commands. He reinforced her understanding with praise and play.

Now one of Pilley's YouTube videos demonstrates how Chaser may understand these grammatical elements together in a sentence.

In the video (shown above), two of Chaser's toys are placed on opposite sides of a room (one toy is named "leopard," the other "ringneck"). When Chaser is told "to leopard, take ringneck," she follows the command by picking up "ringneck" and dropping it by "leopard."

Dr. Pilley wrote in his study's abstract that Chaser's understanding of such sentences was tested with multiple and familiar objects, as well as novel objects. She was even tested when she couldn't see the objects at the time she received a command. The study published online in the journal Learning and Motivation on May 13, 2013.

"Findings were statistically significant in all three scenarios," Dr. Pilley wrote. "Successful findings were attributed to Chaser's intensive training in her first three years of life."

Dr. Stanley Coren, a psychology professor at the University of British Columbia and an expert on canine intelligence, told The Huffington Post that similar studies showing dogs understanding simple two-word sentences -- such as "pull toy" or "fetch ball" -- have been repeated before.

Dr. Coren was not involved in Dr. Pilley's research.

So, just how smart are dogs?

"Roughly speaking, the average dog is equivalent to a human two-year-old in terms of mental abilities," Dr. Coren said. "And the 'super dogs' are equivalent to maybe a human two-and-a-half-year-old.”

"Super dogs" are breeds ranked in the top 20 percent of canine intelligence, Dr. Coren said. Border collies are considered the most intelligent, followed by poodles and German shepherds.

No matter what the breed, the key to teaching dogs to understand commands is repetitive training, Dr. Coren said, adding that simple commands and consistency are also essential.

"I always use exactly the same words and I always use the words to precede an action," Dr. Coren told The Huffington Post. "I’ll say to my dogs 'upstairs' when I’m going upstairs or 'downstairs' when I’m going downstairs. And so, next time you say 'upstairs,' they'll start looking for stairs to climb."